/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 */
package org.geotools.gml2;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Set;

import org.eclipse.xsd.XSDSchema;
import org.geotools.data.DataUtilities;
import org.geotools.xml.SchemaLocationResolver;
import org.geotools.xml.XSD;


/**
 * XSD instance for an application schema.
 * <p>
 * Copied from org.geotools.gml3 making use of addDependencies with our gml2.GML instance.
 * </p>
 * @author Justin Deoliveira, The Open Planning Project
 *
 * @source $URL: http://svn.osgeo.org/geotools/trunk/modules/extension/xsd/xsd-gml2/src/main/java/org/geotools/gml2/ApplicationSchemaXSD.java $
 */
public class ApplicationSchemaXSD extends XSD {
    /** application schema namespace */
    private String namespaceURI;

    /** location of the application schema itself */
    private String schemaLocation;

    public ApplicationSchemaXSD(String namespaceURI, String schemaLocation) {
        this.namespaceURI = namespaceURI;
        this.schemaLocation = schemaLocation;
    }

    protected void addDependencies(Set dependencies) {
        dependencies.add(GML.getInstance());
    }

    public String getNamespaceURI() {
        return namespaceURI;
    }

    public String getSchemaLocation() {
        return schemaLocation;
    }

    /**
     * Uses the <code>schema.getSchemaLocation()</code>'s parent
     * folder as the base folder to resolve <code>location</code> as a
     * relative URI of.
     * <p>
     * This way, application schemas splitted over multiple files can be
     * resolved based on the relative location of a given import or
     * include.
     * </p>
     *
     * @param schema
     *            the schema being resolved
     * @param uri
     *            not used as it might be an empty string when location
     *            refers to an include
     * @param location
     *            the xsd location, either of <code>schema</code>, an
     *            import or an include, for which to try resolving it as
     *            a relative path of the <code>schema</code> location.
     * @return a file: style uri with the resolved schema location for
     *         the given one, or <code>null</code> if
     *         <code>location</code> can't be resolved as a relative
     *         path of the <code>schema</code> location.
     */
    public SchemaLocationResolver createSchemaLocationResolver() {
        return new SchemaLocationResolver(this) {
                public String resolveSchemaLocation(XSDSchema schema, String uri, String location) {
                    String schemaLocation;

                    if (schema == null) {
                        schemaLocation = getSchemaLocation();
                    } else {
                        schemaLocation = schema.getSchemaLocation();
                    }

                    String locationUri = null;

                    if ((null != schemaLocation) && !("".equals(schemaLocation))) {
                        String schemaLocationFolder = schemaLocation;
                        int lastSlash = schemaLocation.lastIndexOf('/');

                        if (lastSlash > 0) {
                            schemaLocationFolder = schemaLocation.substring(0, lastSlash);
                        }

                        if (schemaLocationFolder.startsWith("file:")) {
                            try {
                                schemaLocationFolder = DataUtilities.urlToFile(
                                        new URL(schemaLocationFolder)).getPath();
                            } catch (MalformedURLException e) {
                                // this can't be a good outcome, but try anyway
                                schemaLocationFolder = schemaLocationFolder.substring("file:".length());
                            }
                        }

                        File locationFile = new File(schemaLocationFolder, location);

                        if (locationFile.exists()) {
                            locationUri = locationFile.toURI().toString();
                        }
                    }

                    if ((locationUri == null) && (location != null) && location.startsWith("http:")) {
                        locationUri = location;
                    }

                    return locationUri;
                }
            };
    }
}